Laser Cut Trebuchet

A trebuchet is a type of catapult, a common type of siege engine which uses a swinging arm to throw a projectile. The word trebuchet comes from the Middle French verb "trebuch," meaning ‘to tumble’ or ‘to fall over,’ which is exactly what the throwing arm of a trebuchet does when it is released.

In order to properly complete this laser cut trebuchet, you will need several different things:

1. This Onshape Document
   1. Onshape is a 3D CAD software that allows you to virtually create a model of a soon to be, tangible object
2. A laser cutter or a 3D printer
   1. Based on my particular design you are able to 3D print each part or cut each on out on a laser cutter
3. Wood
   1. As my wood of choice, I chose Luan
   2. I chose this specifically because of the thickness of .189 inches
   3. This thickness allows the Luan to be easily cut by any laser cutter
   4. If you happen to chose a different type of wood you will have to modify the dimensions of all the parts in the CAD file (specifically the mesh points)
4. Glue
   1. Any wood glue will work

• After properly analyzing the full design you can begin modifying it to your own satisfaction
• Remember, if you modify the thickness of the whole design you will also need to change the length and the outward protrusion of the mesh points
• After the model is modified insert each part into a C sized sheet of drawing paper and create your engineering drawing

• After step two is complete you will need to export a PDF file of the final drawing and import it into Adobe Illustrator
  • Go to this link for help

• Now that you have inserted the document into Adobe and then cut it out on your laser cutter you can begin assembly
• Go to this link for help on the tangible assembly
• If the pieces do not quite fit together you can file, sand, and then use the wood glue that was on the list in step one
• When using the Trebuchet, in order to receive the best results, you should have approximately 170 grams in your counterweight, and your projectile should be about 5 grams in weight and 6 inches long in length.
  • Any counterweight can be used
  • I have made my projectile out of two rubber bands, a nut, and a bolt as you can see in the picture above
  • As my counterweights, I have use bolts and ball bearings

In this last step, I have inserted a video of the final product in action.

When analyzing each design you may find that the parts don’t fit together flawlessly. This is because the measurements and dimensions are slightly off; some filing and sanding may be required to assemble the final product. These errors have occurred because of careless measuring.

Some of the information and/or images in this instructable was not my own work. Here are the proper citations crediting the information I have utilized.

“Arms and Men: The Trebuchet.” HistoryNet, 23 June 2016, www.historynet.com/weaponry-the-trebuchet.htm.

Abong.com, director. YouTube. YouTube, YouTube, 19 Oct. 2018, www.youtube.com/watch?v=prfnE_NYrOM&index=2&list=PLYni2YABNDMcOovAMoXULY_R-y4dTlYNk.